The invention relates to a conduit connection assembly, a turbo charger for an internal combustion engine, an internal combustion engine and a vehicle.
In typical vehicles, conduits provide air to an internal combustion engine of the vehicle, and guide exhaust gases from the engine. Engine operation may cause pulsations in such conduits, which may have detrimental effects to devices in the conduits or the operation of the engine. This problem is particularly pronounced where the engine is provided with a turbo charger, and the conduits are located where high pressures occur during turbo charger operation.
US2013111901A1 describes for a turbo charged engine a pulsation absorption device with a resonator, a diaphragm, or a bladder, in order to avoid compressor surge which according to US2013111901A1 might be caused by pulsations in the exhaust flow. ER2879689A1 describes a damping chamber on a compressor side of a turbo charger for reducing pressure pulses from the compressor. However, such known pulsation damping devices are complex and therefore add cost to the vehicle. Also, said FR2879689A1 does not provide any relief of pressure pulses on the turbine side of the turbo charger. Where a device according to said US2013111901A1 is placed on the turbine side, upstream of a turbo charger, the reduced peak pressure can reduce the performance of the turbo charger.
DE2239314 presents openings which extend from a flanged connection of a conduit, and it is suggested that this provides drainage of leakage. However, there is still a desire to reduce the risk of leakage at conduit connections, for example in air and exhaust conduit connections for vehicle internal combustion engines.
It is desirable to reduce the effect of pressure pulses in conduits, in particular conduits of, or connected to, an internal combustion engine. It is also desirable to reduce the effect of pressure pulses in conduits connecting an engine block of an internal combustion engine to a turbo charger. It is also desirable to reduce the risk of leakage in conduit connections exposed to high pressures.
According to an aspect of the present invention, a conduit connection assembly is provided comprising a first conduit part and a second conduit part, adapted to be assembled to form a conduit connection delimiting a first fluid conducting volume, characterized in that the conduit connection assembly presents a second fluid conducting volume, the first and second fluid conducting volumes being arranged to communicate with each other via a pressure change inducing device so as to form a common fluid guide, whereby during use of the conduit connection assembly the pressure in the first conducting volume is higher than the pressure in the second conducting volume, in that a cavity is formed between the first and second conduit parts at a distance from the first conducting volume, and in that a draining connection is adapted to provide a communication between the cavity and the second fluid conducting volume.
The pressure change inducing device may be e.g. a turbine of a turbo charger, a compressor of a turbo charger, an exhaust brake, or a turbo compound unit. It should be noted that the invention is applicable, not only to exhaust and air intake systems for internal combustion engines, as exemplified below. The invention may be used in any suitable application with a conduit presenting a conduit connection which may be subjected to a high pressure and/or pressure pulses, and there is a pressure change inducing device along the conduit. Uses may be found e.g. in air conditioning systems, fuel systems or cooling systems.
Due to the distance between the first conducting volume and cavity, it will be possible to restrict, e.g. as exemplified below, the transport of fluid from the first conducting volume to the cavity, i.e. fluid transport to the cavity radially inside of the cavity. The first and second conduit parts may be adapted to form, in their assembled state, a sealing abutment radially outside the cavity. The cavity and the sealing abutment may extend around the fluid conducting volume, preferably forming respective closed loops. The first and second conduit parts may be adapted to form the sealing abutment by directly contacting each other, or by a sealing element between the first and second conduit parts, which sealing element may be a gasket.
During use of the conduit connection assembly, e.g. during operation of an engine with which it communicates, since the pressure in the first conducting volume is higher than the pressure in the second conducting volume, the draining connection will provide a flow from the cavity to the second fluid conducting volume. By means of the draining connection, it will be possible to reduce the exposure of the sealing abutment radially outside of the cavity to pressure pulses as well as a high mean pressure in the first fluid conducting volume. The combination, herein also referred to as a pressure reducing volume, of the draining connection and the cavity provides for an effective evacuation of first fluid conducting volume pressure affecting the sealing abutment. The pressure reducing volume provides a communication between the interface between first and second conduit parts and the second fluid conducting volume. The draining connection bypasses the pressure change inducing device. Thereby, the draining connection provides for fluid, being transported or “leaking” between the first and second conduit parts, from the first fluid conducting volume to the cavity, to bypass the pressure change inducing device. Thereby the pressure in the cavity may be reduced and the stress on the sealing abutment, radially outside of the cavity, will be reduced.
The first and second conduit parts may present respective connection surfaces adapted to face each other. The cavity may be at least partly formed by at least one of the connection surfaces and/or partly located directly adjacent at least one of the connection surfaces.
According to another aspect of the invention, a conduit connection assembly is provided comprising a first conduit part and a second conduit part, adapted to be assembled to form a conduit connection delimiting a fluid conducting volume, wherein one of the first and second conduit parts presents a connection surface adapted to face the other of the first and second conduit parts, wherein a pressure reducing volume is at least partly formed in the connection surface, wherein the pressure reducing volume is partly formed by a cavity, and the first and second conduit parts are adapted to form, in their assembled state, a sealing abutment radially outside the cavity, wherein the pressure reducing volume presents a draining connection, wherein the conduit connection assembly further is adapted to present, in its assembled state, a second fluid conducting volume, the draining connection being adapted to provide a communication between the cavity and the second fluid conducting volume, wherein the first fluid conducting volume is adapted to communicate with an internal combustion engine, whereby during operation of the internal combustion engine, the pressure in the first conducting volume is higher than the pressure in the second fluid conducting volume.
Providing the pressure reducing volume at least partly formed in the connection surface allows for local pressure pulse reduction or damping to reduce pressure pulse effects to the connection. For example, where a seal or gasket is provided at the connection, the wear of the seal may be reduced, so that the life of the seal may be increased, and/or the use of simpler and less costly seals may be allowed. In particular, where the connection is provided in a conduit connecting an engine block to a turbo charger, whereby the connection is exposed to a high pressure during turbo charger operation, the pressure reducing volume formed in the connection surface will considerably reduce the effects of pressure pulses to a sealing abutment of the connection. E.g., where such an abutment includes a gasket, the invention may allow for a cheap one layer stainless steel gasket to be used instead of an expensive three layer nickel-chromium alloy gasket.
Also, the local pressure pulse reduction aimed at reducing pressure pulse effects on the connection, makes it possible to retain the pressure pulses in the first fluid conducting volume, which is beneficial to a turbo charger operation where the connection is provided upstream of a turbine charger, on the turbine side thereof.
Since the first and second conduit parts are adapted to form, in their assembled state, a sealing abutment radially outside the cavity, the pressure reducing volume can provide a barrier to the sealing abutment to protect it against pressure pulses.
Since the pressure reducing volume presents a draining connection, it will, as also suggested above, be possible to reduce the exposure of a sealing abutment in the conduit connection assembly to a high mean pressure in the first fluid conducting volume. For example, in combination with a narrow slot, exemplified closer below, providing a communication between the first fluid conducting volume and the pressure reducing volume, e.g. with a slot width of 0.001-1 mm, preferably 0.005-0.5 mm, more preferably 0.01-0.1 mm, any diversion of a flow in the first fluid conducting volume into the draining connection will be kept advantageously small. In combination with the cavity, presenting a closed loop shape, e.g. by being ring shaped, and extending around the first fluid conducting volume, a homogenous and rapid evacuation of fluid conducting volume pressure affecting the sealing abutment can be provided.
As exemplified further below, to effectively reduce peak pressure impact on the connection, the pressure reducing volume is preferably specifically adapted to reduce pressure pulses from the first fluid conducting volume.
Preferably, the pressure reducing volume is at least partly delimited by the first conduit part as well as the second conduit part. This allows for simple manufacturing of the pressure reducing volume, since the connection surfaces may be easily accessible for some of the manufacturing measures before assembly of the conduit connection assembly, leaving the completion of a substantially enclosed pressure reducing volume to be provided as a result of the assembly.
Preferably, the pressure reducing volume is at least partly formed by a depression in the connection surface. By forming at least a part of the pressure reducing volume by such a depression, the provision of the pressure reducing volume during manufacturing may be facilitated.
Preferably, the cavity is close loop shaped, e.g. ring shaped, and extends around the first fluid conducting volume. Thereby, the cavity can be arranged to be distributed along a sealing abutment of the conduit connection assembly, thereby providing a local and effective protection of the abutment against pressure pulses on the first fluid conducting volume.
Preferably, the conduit connection assembly may present a slot adapted to provide a communication between the first fluid conducting volume and the pressure reducing volume. Such a slot will together with the pressure reducing volume contribute to the reduction of pressure pulses from the first fluid conducting volume. Preferably, the first and second conduit parts are adapted to form the slot in their assembled state. Thereby, the slot may be provided in a simple manner during manufacturing by assembling the first and second conduit parts.
Preferably, the pressure reducing volume is 5,000 to 50,000 times larger than a volume occupied by the slot. Such a high ratio of the volume of the pressure reducing volume and the volume occupied by the slot will effectively reduce the peak pressures of the pressure pulses in the first fluid conducting volume, and may thereby reduce pressure peak exposure to a sealing abutment of the conduit connection assembly.
Preferably, the cavity and the slot are closed loop shaped, e.g. ring shaped, and extending around the first fluid conducting volume, the cavity presents, in a cross-section perpendicular to a circumferential direction of the first fluid conducting volume, a cross-sectional area which is 100,000 to 1,000,000 times larger than the slot width squared. This will further secure a reduction peak pressure exposure to a sealing abutment of the conduit connection assembly. It should be noted that the circumferential direction of the first fluid conducting volume is preferably defined by the local direction of a gas flow in the first fluid conducting volume. The local direction of the gas flow is the direction of the gas flow at the conduit connection. The circumferential direction is a direction which is perpendicular to an axial direction of the gas flow, and perpendicular to a radial direction of the gas flow.
Preferably, the slot extends at least partly in an axial direction of the conduit connection assembly in its assembled condition. An axial extension of the slot will facilitate production with high tolerance requirements on the slot. In some embodiments however, the slot extends at least partly in a radial direction of the conduit connection assembly in its assembled condition. It should be noted that the axial direction of the conduit connection assembly is preferably defined as the local direction of a gas flow in the first fluid conducting volume, at the conduit connection. The radial direction of the conduit connection assembly is perpendicular to said axial direction.
Preferably, the width of the slot is 0.001-1 mm, preferably 0.005-0.5 mm, more preferably 0.01-0.1 mm. Such a relatively low slot width will, in connection to a relatively large pressure reducing volume, provide a particularly effective peak pressure damping, especially where the conduit connection assembly is provided in an exhaust or inlet system of a vehicle.
Preferably, the slot extends around the first fluid conducting volume, and the length of the slot, as seen in a cross-section perpendicular to a circumferential direction of the first fluid conducting volume, is at least 0.5 mm, preferably at least 1 mm, more preferably at least 2 mm. Such a slot length will provide a dimension of the slot facilitating manufacturing, while retaining an effective pressure pulse damping contribution.
Preferably, the slot extends around the first fluid conducting volume in the circumferential direction. The slot may present the shape of a closed loop. The slot may be e.g. ring shaped. The width of the slot may be defined as the smallest dimension of the slot. The length of the slot may be the dimension of the slot following the shortest distance of communication provided by the slot, from the first fluid conducting volume to the pressure reducing volume.
The cavity and the sealing abutment may extend around the first fluid conducting volume, preferably forming respective dosed loops. The cavity may be at least partly formed by a depression in the connection surface.
The first and second conduit parts may be adapted to form the sealing abutment by directly contacting each other. Thus, a sealing element, such as a gasket, is omitted, which is made possible by the pressure reducing volume reducing pressure pulses, and this will reduce complexity and cost of the conduit connection assembly.
Alternatively, the first and second conduit parts might be adapted to form the sealing abutment by a sealing element, which might be a gasket, between the first and second conduit parts. As mentioned, in such embodiments, the invention makes it possible to use simpler and less costly sealing elements.
Preferably, the first conduit part is a turbine inlet conduit of a turbo charger for an internal combustion engine. The second conduit part might be an exhaust gas conveying part, e.g. an exhaust gas outlet manifold, adapted for conveying exhaust gases from an internal combustion engine. Thereby, the invention will be implemented to provide an effective protection of a sealing abutment at the taxing environment of the exhaust gas stream with the pressure pulses from the engine.
The invention may also be implemented to provide an effective protection of a sealing abutment at other locations with challenging environments, e.g. with high pulsating pressures. The first conduit part might be a compressor outlet conduit of a turbo charger for an internal combustion engine. The second conduit part might be a charged air conduit for an internal combustion engine. The first conduit part can be an intercooler for an air inlet of an internal combustion engine. The first conduit part might be an internal combustion engine and the second conduit part can be an air inlet manifold or an exhaust gas outlet manifold. The first conduit part might be a turbo compound unit.
Preferably, the draining connection is adapted to provide a communication between the first and second fluid conducting volumes.
The pressure in the first conducting volume being, during operation of the internal combustion engine, higher than the pressure in the second conducting volume, might be due to the first fluid conducting volume being, in the assembled state of the assembly, partly formed by a turbine inlet conduit of a turbo charger for an internal combustion engine, and the second fluid conducting volume being at least partly formed by a turbine outlet conduit of the turbo charger. Thereby, due to the draining connection, the sealing abutment of the conduit connection assembly will be exposed to substantially the same pressure as that in the second fluid conducting volume. This will considerably reduce the high pressure exposure to the sealing abutment. This lower pressure will also contribute to reducing or eliminating the exposure of the sealing abutment to pressure pulses in the first fluid conducting volume. At the same time, the high pressure and the pressure pulses may be retained in the first fluid conducting volume, thereby retaining a high turbo charger efficiency.
It should be noted that preferably the cavity in completely enclosed, apart from the communication with the slot and the communication with the draining connection.
According to another aspect of the invention, a turbine inlet conduit for a turbo charger for an internal combustion engine is provided, wherein the turbine inlet conduit is adapted to be assembled to another conduit part, and presents a connection surface adapted to face the other conduit part, wherein a depression is formed in the connection surface whereby the depression is adapted to form, when the turbine inlet conduit is assembled to the other conduit part, at least a part of a pressure reducing volume.
Preferably, the depression presents a closed loop shape, e.g. by being ring shaped, and is adapted to extend around a fluid conducting volume formed by the turbine inlet conduit and the other conduit part in their assembled condition.
According to another aspect of the invention, a turbo charger for an internal combustion engine is provided, comprising a turbine inlet conduit, the turbine inlet conduit being adapted to be assembled to another conduit part, and presenting a connection surface adapted to face the other conduit part, wherein a depression is formed in the connection surface whereby the depression is adapted to form, when the turbine inlet conduit is assembled to the other conduit part, at least a part of a pressure reducing volume, the turbo charger further comprising a turbine outlet conduit, and a draining connection an adapted to provide a communication between the depression and the turbine outlet conduit.
According to another aspect of the invention, an internal combustion engine or a vehicle provided with a conduit connection assembly, or a turbo charger is provided.